The Dragon has to survive reentry into the atmosphere and
splashdown into the Pacific Ocean. The intention is to then reuse
it for future missions. If it succeeds, it will be huge news for
the future of private space exploration.

The launch is scheduled to occur at 4:55 AM EST tomorrow,
exactly. If it doesn't occur then, the launch will need to be
delayed until May 22. That is because the space station will be
in the wrong position to pair with the Dragon.

It is that precise. Best of luck to SpaceX, we sincerely hope
they succeed.